Light-emitting device and lighting device

Abstract

Provided is a light-emitting device having a structure in which a high refractive index component is provided between a solid light-emitting element and air, has an uneven structure on a surface in contact with air, and can be reused. The light-emitting device includes a substrate having a refractive index of 1.6 or higher and a light-transmitting property, a solid light-emitting element including a light-emitting region having a refractive index of 1.6 or higher on one surface of the substrate, and a component having a refractive index of 1.6 or higher and a light-transmitting property on the other surface of the substrate, wherein the component includes an uneven structure on a surface in contact with air and is connected to the substrate via a liquid having a refractive index of 1.6 or higher and a light-transmitting property.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to light-emitting devices and lighting devices each using a solid light-emitting element.[0003]2. Description of the Related Art[0004]In a solid light-emitting element in which light is emitted in a medium having higher refractive index than air, incident light from a high refractive index region to a low refractive index region with an angle larger than the critical angle is fully reflected on an interface. A variety of techniques has been developed in order to extract light of the solid light-emitting element efficiently.[0005]For example, a technique is known in which incident light to a low refractive index region with an angle larger than the critical angle is prevented from being fully reflected repeatedly with the use of a structure in which a high refractive index region is connected to the low refractive index region via an interface that has an uneven structure.[0006]In Non-Patent...

AI Technical Summary

Benefits of technology

[0009]In addition, the light-emitting element has a function of converting electric energy into optical energy. A reduction in emission efficiency due to the use of the light-emitting element and a degradation phenomenon thereof are difficult to avoid. In contrast, the uneven structure mainly has a function of controlling reflection of light; thus, degradation is less likely to occur than in the light-emitting element. That is, it can be said that the lifetime as a component included in a light-emitting device differs between the solid light-emitting element and the uneven structure that increases the light extraction efficiency thereof.

[0016]According to one embodiment of the present invention described above, with the use of a high refractive index liquid, the high refractive index component can be optically connected to the high refractive index substrate without generating a layer with a low refractive index therebetween (e.g., air); thus, high light extraction efficiency can be realized. In addition, with the use of a liquid having fluidity, the component can be detached from the substrate and the component can be reused.

[0018]According to one embodiment of the present invention described above, light emission can be extracted with high efficiency from a light-emitting region which is spread out in a plane, through a first electrode having a light-transmitting property. In addition, with the use of a liquid having fluidity, the component can be detached from the substrate and the component can be reused.

[0020]According to one embodiment of the present invention, it is possible to provide a light-emitting device having a structure in which a high refractive index component is provided between a solid light-emitting element and air, has an uneven structure on a surface in contact with air, and can be reused.

Problems solved by technology

In order to realize such a structure, the uneven structure needs to be formed intentionally at an interface in contact with air, and accordingly, the fabrication process of the light-emitting device is complicated.

A reduction in emission efficiency due to the use of the light-emitting element and a degradation phenomenon thereof are difficult to avoid.

Therefore, in the case where the uneven structure is formed so as not to be separated from the light-emitting element, when the performance of the light-emitting element becomes low or when the light-emitting element is degraded or broken, the uneven structure would be wasted together with the light-emitting element.

Thus, there is a problem in that the time and energy that have been spent on forming the uneven structure and materials included in the uneven structure would be wasted in vain.